Bio study doc Topics: ➢ Classification ➢ Cells ➢ Nutrition Classification The first way to classify animals was based on their observable characteristics - First done by Aristotle in 4th Century B.C.E Some ways Aristotle classified animals were: - If they laid eggs vs having live young - If they had blood vs having no blood - Whether they live in water or on land - Their methods of locomotion - Behavioural Patterns - Physical features such as size, shape, skin, color, presence or absence of wings and other physical attributes Dichotomous key - A tool used to identify specific organisms based on a series of two choices which can be answered either with yes or no which may lead to another series of two choices. Linnaean System & Binomial Nomenclature Carl Linneaus, also known as the father of taxonomy, created the first edition of the Linnaean System in the 1735, before finalizing it in 1758 Carl Linneaus created and published the naming system known as the Binomial Nomenclature in 1758 Note: - An organism’s genus is always written first then its species - Only the first letter of said genus is capitalized, everything else is written in common letters. - Both the genus and species are written separately as two different words, not written attached together - When writing, the genus and species are underlined separately whilst when typing they are either underlined or italicized. (Observe the image below) Homo sapiens -> Homo sapiens Taxonomy is termed as the science of defining and naming biological organisms on the basis of shared characteristics The modern system of classification as 7 levels of taxa: Kingdom is defined as the least specific level whilst at the species level, classification is most specific. A mnemonic used to remember the seven levels in order is: Katy Please Come Over For Ginger Snacks Kingdom Phylum Class Order Family Genus Species Kingdoms There are 5 Kingdoms: Monera, Protista, Plantae, Animalia, Fungi The highlighted 4 are Eukaryotes. The highlighted 1 are Prokaryotes. Animal Kingdom Characteristics of animal kingdom organisms - Multicellular - Eukaryotes - Usually reproduce sexually - Have many specialized parts (physical features like gills and wings, and internal features like different types of cells (heart cell vs brain cell), organs, tissues etc.) - Are able to move - Heterotrophs (depend on other organisms for food) - Can be bilateral and radial in symmetry Kingdom is split into Vertebrates and Invertebrates (majority of animals are Invertebrates) Vertebrates All vertebrates fall under the phylum : Chordata There are 5 groups of vertebrates: Mammals, Birds, Reptiles, Fish, Amphibians Mammals - Have hair or fur and produce milk - Specialized teeth - Give birth to live offspring (no eggs) - Have a four chambered heart - Endothermic (body temperature doesn’t change even if the environment changes - warm blooded) Birds - Have feathers, scales on feet and legs and hollow bones - Have a gizzard that hold small stones that help to grind food - Have a four chambered heart - Lay hard shelled eggs - Endothermic Fish - Have wet scales - Lay eggs in water - Lives in water - Uses gills for breathing - Ectothermic (body temperature changes with the environment - cold blooded) Amphibians - Have moist skin - Obtains oxygen through lungs and skin - Lay jelly coated eggs in water - Lives on land and water - Ectothermic Reptiles - Have dry scales - Lay waterproof eggs on land - Skin is adapted to keep water in the body - Breathe through lungs - Ectothermic Invertebrates Invertebrates fall under 29 different Phylums (there’s 8 on the ppt so like…) There are 8 groups of invertebrates: Porifera, Platyhelminthes, Annelida, Nematoda, Arthropods, Molluscs, Cnidarians, Echinoderms Porifera (Sponges) - Filter feed (force water through pores and consumes what can’t pass through pores) - Simplest animals (thin layers of cells are protected by a jelly layer) - Asymmetrical - Reproduce sexually and asexually Platyhelminthes (Flatworms) - Have flat worm bodies - Bilateral symmetry - Have head and tail ends - Simplest organism with a brain - E.g.: tapeworms and planarians Annelida (Segmented Worms) - Have bodies made of many linked sections - Bilateral symmetry - Have head and tail ends - Simplest organism with a brain - E.g.: earthworms and leeches Nematoda (Roundworms) - Digestive system is like a tube open at both ends - Have bodies with no segments hence term ‘round’ worms - Have head and tail ends - Simplest organism with a brain - Bilateral symmetry - E.g: Ascaris, root knot nematode, heartworm, pinworm Arthropods - Have segmented bodies - Have jointed appendages - Have an external skeleton - 4 groups: Arachnida, Crustacean, Insecta, Myriapoda Mollusks - Soft bodies, some have a hard outer shell, foot for moving - Bilateral symmetry - Three groups: Gastropod -> most diverse (ex. snails, slugs), Bivalve (Ex. Clam, Mussels), Cephalopod (Ex. Octopus, Squid) Cnidarians - Have stinging tentacles - Radial symmetry - Two body forms : Medusa (the form during the movement stage in life) & Polyp (sessile - doesn’t move) Echinodermata - Have radial symmetry - Have spiny outer covering - Have a water vascular system - E.g: starfish and sea urchins Plant kingdom Plant is divided into 2 groups: Flowering Plants(has seeds) and Non-Flowering Plants(has no seeds) Non- Flowering Plants Divided into 3 groups: Bryophyta, Pteridophyta & Gymnosperms Bryophyta(Mosses) - Simplest Plants - No true roots, no vascular tissues (no transport) - Simple stems & leaves - Have rhizoids for anchorage - Spores from capsule (wind dispersal) - Damp terrestrial land (location) Pteridophyta(Ferns) - Roots, feathery leaves & underground stems - Have vascular tissues (transport and support - Spore producing organ on the underside of leaves (reproduction) - Damp & shady areas (location) Gymnosperms - Tall evergreen trees - Roots, woody stems - Needle shaped leaves - Vascular tissues (transport) Cones with reproductive structures Naked seeds in female cones Dry places (location) Flowering Plants Divided into 2 groups: Monocotyledons & Dicotyledons ● Have roots, stems, leaves ● Vascular tissues (transport) ● Flowers, fruits (contains seeds) Monocotyledons - One seed leaf - Leaves have parallel veins - Herbaceous plants - E.g: grass, maize Dicotyledons - Two seed leaves - Leaves have vein in network - E.g: trees, sunflower, rose Fungi Kingdom Characteristics of Fungi - Nonphotosynthetic Most are multicellular except unicellular yeast Eukaryotes Nonmotile (generally) Most are saprobes (live on dead organisms) - Important decomposers & recyclers of the nutrients in the environment - Lack true roots, stems or leaves - Absorptive heterotrophs (digest food first & then absorb it into their bodies) - Release digestive enzymes to break down organic material or their host - Store food energy as glycogen - Cell walls are made of chitin - Body is called thallus - Grow as microscopic tubes called hyphae - Some are edible whilst some are poisonous - Produce both sexual and asexual spores - Grow best in warm, moist environments - Mycology is the study of fungi & a person who studies Mycology is called a Mycologist Protist Kingdom Comparison to bacteria Similarities - Unicellular - One of the first groups on earth - Microscopic - Can cause diseases - Can be parasites Differences - Has a nucleus - Live in watery environments - Generally live as individual cells - Vary greatly in appearance and function 3 Categories: Animal-like Protists, Plant-like Protists and Fungi-like Protists Animal-like Protist - Protozoan meaning ‘first animal’ - Cells contain a nucleus - Cells lack a cell wall - They are heterotrophs - Most can move on their own Plant-like Protist - Unicellular and Multicellular - Colonies (groups of unicellular protists) - Can move on their own - Autotrophs (make their own food with aid of photosynthesis) - 70% of oxygen is produced by plant like protist (algae) - Pigments: chemicals (proteins) that produce color Fungus-like Protist - Heterotrophs - Have cell walls - Many have flagella and are able to move at some point in their lives - Three types: Water molds, Slime molds & Downy molds - Reproduce with spores (tiny cells that is able to grow into a new organism) Monera Kingdom - Monera kingdom is basically Prokaryotes / Bacteria General Features and Domain Cells Bacterial Cells Structure purposes ➢ Capsule - found in most bacterial cells, additional protection when eaten by other organisms, assist in retaining moisture, helps the cell adhere to surfaces and nutrients ➢ Flagella - long, whip-like protrusion that aids in cellular locomotion ➢ Nucleoid Region - Area of the cytoplasm that contains singular DNA molecule ➢ Pili - hair-like structures on the surface of the cell that attach to other bacterial cells that allow the transfer of plasmids. The smaller version, fimbriae, helps bacteria attach to host cells or other surfaces ➢ Plasmids - circular piece of DNA. The genes carried in plasmids provide bacteria with genetic advantages such as antibiotic resistance Shared Structures Animal Cells Structure purposes ➢ Cell membrane - the thin layer of protein and fat that surrounds the cell and is selectively-permeable / partially permeable ➢ Centrosome - during mitosis, the centrosome divides the cell and splits between the 2 halves ➢ Cytoplasm - the jellylike material where the organelles of the cell are located (outside the nucleus) ➢ Ribosome - rich cytoplasmic granules which are composed of RNA and are the site of protein synthesis ➢ Golgi body - the sac like organelle located near the nucleus that packages proteins and carbohydrates into membrane-bound vesicles for ‘export’ from the cell. ➢ Lysosomes - round organelles surrounded by a membrane that is the site of digestion of cell nutrients in the cell ➢ Mitochondria - converts energy stored in the glucose into ATP for the cell ➢ Nuclear membrane - membrane surrounding the nucleus ➢ Nucleus - spherical body that contains the nucleolus and controls many functions of the cell and contains DNA ➢ Nucleolus - organelle within the nucleus that contains RNA ➢ Rough Endoplasmic Reticulum (Rough ER) - transports materials through the cell and produces proteins in sacs called cisternae ➢ Smooth Endoplasmic Reticulum (Smooth ER) - transports through the cell and contains enzymes and produces and digest lipids and membrane proteins ➢ Vacuole - fluid-filled membrane surrounded cavities inside the cell that fills with food being digested by the cell and waste material that is on its way out the cell. Plant Cells Structure purposes ➢ Amyloplast - an organelle in some plant cells that stores starch ➢ Cell Wall - layer of cellulose fiber that gives the cells most of its support and structure ➢ Chlorophyll - molecule that captures light energy to turn water and carbon dioxide gas into sugar and oxygen ➢ Chloroplast - elongated or disc-shaped organelle containing chlorophyll. Photosynthesis takes place in chloroplasts. Cell Specialization - Cell specialization is non-existent in unicellular - Importance of Cell Specialization - Cell specialization, or cell differentiation, is a crucial aspect of multicellular organisms, dividing labor among cells to perform specific functions. It optimizes efficiency, facilitates tissue formation, and allows organisms to adapt to diverse environments. Cell specialization is essential for regeneration, repair, organ function, and evolutionary adaptation, contributing to the complexity and diversity of life on Earth. Specialized Plant Cells - Onion Epidermal Cell: Epidermal cells protect plants by providing a barrier against damage, secreting substances for herbivores and insects, absorbing water and nutrients, and regulating gas exchange for photosynthesis, with some cells containing chloroplasts. - Guard Cell: Guard cells in plant leaves and stems regulate gas exchange, water loss, and transpiration, responding to environmental cues like light intensity, humidity, and carbon dioxide levels. - Root Hair Cell: Root hair cells in vascular plants perform essential functions like water and nutrient absorption, anchorage, soil particle adhesion, gas exchange, and interaction with soil microorganisms. Specialized Animals Cells - White Blood Cell: White blood cells (WBCs) are crucial in the immune system, defending against infections, promoting overall health, and facilitating antibody production, inflammatory response, and immune memory. - Red Blood Cell: Red blood cells transport oxygen and carbon dioxide, regulate blood pH, and store iron for future hemoglobin synthesis, with a finite lifespan and flexible biconcave shape. - Sperm Cell: Sperm cells are specialized reproductive cells responsible for sexual reproduction, egg fertilization, genetic diversity, and the acrosome reaction for genetic material union. - Nerve Cell: Neurons are vital for the nervous system, transmitting signals, integrating information, controlling muscle contractions, memory, and learning, and communicating with other cells to influence physiological processes. - Muscle Cell: Muscle cells play a crucial role in various physiological functions such as movement, posture, heat production, digestion, blood circulation, joint stabilization, and nutrient storage. Levels of Organization Tissues: a group of similar cells to perform a particular function. Organs: different tissues grouped together to carry out specialized function of an organ Systems: several organs and tissues work together to carry out a particular set of functions in a coordinated way Osmosis & Diffusion - Transport is important to cells for obtaining useful materials and eliminating metabolic waste Permeability in different conditions - Living cell membrane - selectively permeable - Visking tube/Dialysis Tube - selectively permeable - Dead cell membrane - freely permeable - Cell wall - freely permeable Diffusion The movement of molecules down or along a concentration gradient until evenly distributed (fluid/dissolved molecules) Examples of diffusion in living organisms 1) Gas exchange in the respiratory system involves oxygen and carbon dioxide exchange in the lungs during respiration, with oxygen diffused into the bloodstream and carbon dioxide expelled. 2) Nutrient absorption occurs in the digestive system, where nutrients(dissolved molecules) like glucose and amino acids are absorbed into the bloodstream for transport to the body's cells. 3) Waste products like urea diffuse into the kidneys, where they are eventually excreted as urine, demonstrating the process of waste elimination in the excretory system. Osmosis The movement of water molecules down or along a water potential gradient through a selectively permeable membrane Water potential, denoted by Ψ (psi) and expressed in pressure units like megapascals (MPa) in the International System of Units, measures the impact of solute concentration, pressure, and gravity on plant tissue movement. - Red blood cells maintain their normal shape when placed in an isotonic solution, which has the same concentration of solutes as inside the cell. - Osmosis in plant cells maintains turgor pressure, providing structural support. When placed in a hypotonic solution, water swells and turgidifies the cells. - Plasmolysis occurs when plant cells are exposed to a hypertonic solution, causing water to move out, causing the cell membrane to pull away, potentially causing wilting. Active Transport The movement of particles through a carrier channel from low concentration to a high concentration area using energy from respiration - Requires energy & carrier protein - Occurs in living cells only - Molecules move from high to low concentration in high rate – i.e. AGAINST a concentration gradient Nutrition The three types of organisms Autotrophs, detritivores, and decomposers are three types of organisms in ecosystems that play distinct roles in energy and nutrient cycling. Autotrophs produce food through photosynthesis, while detritivores feed on decaying organic matter, breaking down complex compounds into smaller particles. Decomposers specialize in breaking down dead organic matter, aiding in nutrient recycling. Photosynthesis Photosynthesis is a biological process in which green plants, algae, and bacteria convert light energy into chemical energy in the form of glucose. It occurs in chloroplasts, involving sunlight absorption, carbon dioxide absorption, and oxygen release. Photosynthesis is essential for life on Earth, forming food chains and ecosystems. Formula The primary pigment for photosynthesis is Chlorophyll a (absorbs red-orange light) and Chlorophyll b (absorbs blue-violet color light). We see plants as green because chlorophyll reflects the green pigment color to our eyes. Other pigments that absorb light carotenoids, anthocyanins and xanthophylls. Light Dependent and Independent Stages - Light reactions are the ‘photo’ part of photosynthesis where light is absorbed by pigments - Dark reactions (aka Light Independent Stage, Calvin Cycle) are the synthesis part of photosynthesis and glucose is produced during this stage Photosynthesis occurs in the chloroplast overall but occurs specifically in the thylakoid membranes for the light-dependent reactions and in the stroma for the light-independent reactions (Pics basically summarizes photosynthesis) Factors that affect photosynthesis 1) Temperature 2) Availability of Light and Light Intensity 3) Carbon Dioxide Concentration Adaptations of the External Structure of the leaf for photosynthesis The leaf's external structure optimizes photosynthesis efficiency by incorporating key adaptations such as a large surface area, thin structure, transparent epidermis, waxy cuticle, stomata, mesophyll tissue, vascular bundles, and chloroplast distribution. These features enhance the leaf's ability to capture sunlight, exchange gases, and conduct photosynthesis processes. - Large surface area enhances sunlight exposure for chloroplasts, facilitating photosynthesis. Thin structure optimizes gas diffusion, while transparent upper and lower epidermis allows light to penetrate mesophyll cells. - Leaf's outer surface has a waxy cuticle, regulating transpiration and gas exchange, while stomata facilitate photosynthesis and transpiration, allowing carbon dioxide and oxygen exchange. - Mesophyll tissue, composed of chloroplasts, enhances sunlight capture through vascular bundles, distributing water and minerals, and maximizing light absorption during photosynthesis. - Leaves' thin, flattened structure optimizes gas diffusion through surfaces, facilitating photosynthesis and respiration by facilitating the exchange of carbon dioxide and oxygen. - Stomata, tiny pores on leaf surfaces, regulate gas exchange during photosynthesis and transpiration, allowing carbon dioxide and oxygen to enter and exit. - Vascular bundles, containing xylem and phloem, are distributed throughout the leaf, transporting water, minerals, and sugars from the leaf to other parts of the plant. - Chloroplasts are concentrated in mesophyll cells, maximizing light absorption during photosynthesis. The role of the internal structures of the leaf in photosynthesis The leaf's internal structure is designed to facilitate photosynthesis, converting light energy into chemical energy. It maximizes sunlight capture, facilitates gas exchange, and supports photosynthesis biochemical processes. The main structures involved are mesophyll cells, chloroplasts, and vascular tissues. - Mesophyll cells contain numerous chloroplasts, which absorb light energy during light-dependent reactions and participate in light-independent reactions like the Calvin Cycle, where carbon dioxide is fixed to produce sugars. - Leaf vascular tissues, including xylem and phloem, transport water and minerals for photosynthesis. Stomata regulate gas exchange, allowing carbon dioxide and oxygen to enter and exit the leaf. - Chloroplasts, membrane-bound organelles in plant cells, play a crucial role in photosynthesis, absorbing light energy through pigments and facilitating the Calvin Cycle, which produces sugars. Role of HCL in digestion Hydrochloric acid (HCl) is essential for digestion, particularly in the stomach. It activates pepsin, facilitates protein digestion, maintains optimal pH for enzymes, kills microorganisms, aids in mineral absorption, and stimulates hormones. The secretion of HCl is tightly regulated to maintain the balance for optimal digestion, preventing conditions like acid reflux or indigestion.
